City firms – most notably the hedge fund, insurance and commodities sectors – are sick of the “unending blizzard” of regulation coming out of Brussels, says Mr Farage, who claims traditional City Conservative supporters are switching allegiance to UKIP.

“Slowly but surely, donors who would have traditionally supported the Tories are now holding talks with us,” Mr Farage told The Daily Telegraph. “We are asking [City leaders] to help in any way we can.”

The most recent business convert to UKIP is Andy Brough, the star fund manager at Schroders, who is understood to have joined Mr Farage’s party after growing weary with the coalition Government and European attacks on the City.

Mr Farage also has the support of the influential hedge fund manager Crispin Odey, whose former father-in-law is News Corp chairman Rupert Murdoch.

Mr Odey is not a member of UKIP, but threw a party at his Odey Asset Management offices on Thursday night to introduce Mr Farage to potential supporters and donors.

“I did it because I think it is essential for people to hear Nigel’s side of the debate,” said Mr Odey. “The real debate has to be, either we change the constitution of Europe, to make it much more democratic, or we get out.”

Neither Mr Odey nor Mr Farage would name the “wide range” of financial services leaders at the fundraising event. But Mr Farage, who made an hour-long presentation followed by Q&A session, felt there was a “warm sentiment towards our ideas”.

He said: “There is a growing feeling that we should be regulating our own country, with the view that we should be a global, not a European, financial centre.

“It has gone beyond disillusionment. People are wondering what the point of the Conservative party is, now they have handed over all their power to Brussels.”

Mr Odey added: “There is an opportunity to create something great out of the existing structure of Europe, and we should at least offer that up.

“But if and when we exit Europe, at least we can say that it will allow the UK to become far less regulated than we have been.”

Other City supporters of UKIP include Stuart Wheeler, the founder of IG Group, who is the party’s treasurer.